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Hylamer polyethylene was introduced in the 1990s as an alternative to conventional polyethylene. Its chemical and physical properties, and especially its high crystallinity, were claimed to improve resistance to wear. Initially Hylamer devices were sterilized by gamma radiation in air, then the technique was changed and gamma radiation was performed in the absence of oxygen. Clinical experience has shown the early loosening of some devices made from Hylamer. The aim of this study was to ascertain whether early wear and consequent osteolysis was linked to the sterilization method. We retrospectively compared 31 patients with hip prostheses with Hylamer liners sterilized by gamma radiation in air (group 1) with 30 patients with the same prosthesis, but sterilized in the absence of oxygen (group 2). The groups were similar for sex, age, disease, head diameter and material. Mean follow-up was 84 months and no clinical signs of failure were present. Radiographic measurement revealed that wear of group 1 was significantly greater than that of group 2 (0.23 mm/year vs 0.09 mm/year, p=0.001). Periacetabular and femoral osteolysis in group 1 was significantly greater than group 2. In conclusion, the method of sterilization might have influenced the outcome of Hylamer polyethylene liners. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study was to investigate the outcome of dual-mobility cup (DM) compared with a standard cup (SC) in primary total hip arthroplasty (THA) in the long-term follow-up based on a regional Italian joint registry (RIPO)., Methods: The Registry of Prosthetic Orthopaedic Implant (RIPO) was consulted, looking for all primary THAs implanted from 2000 to 2019. Three thousand seven hundred ten were dual-mobility cup (DM) total hip arthroplasties (THA) and 85.816 were standard cup (SC) THAs, on a total of 89.526 primary THA. Demographics, survival rates and causes of revision were evaluated and compared between the two groups., Results: The use of DM progressively increased from 0.4% in 2000 to 7.5% in 2018 of all primary THAs. Revision rate was 3.5% (128 on 3710) for DMC and 4.7% (4061 on 85,816) for SC. DM presented lower dislocation rate if compared to SC with 22-28-mm femoral head diameter. However, DM showed a higher risk of revision for any causes than SC with 32-mm femoral head diameter in long-term follow-up. Nevertheless, no significant difference was measured in terms of demographics and surgical approach for dislocation rate., Conclusions: The DM cup represents a valid implant solution and has a lower dislocation rate than 22-28-mm SC. A slight increase in the use of DM implants over time was observed in the RIPO. However, a larger population and a longer follow-up are needed to further monitor the survival rate of new-generation DM implants., (© 2022. The Author(s).)

Purpose: Surgical options for long bone metastases include intramedullary nail fixation or prosthetic reconstruction. Patients with a short life expectancy may benefit from less invasive surgery such as intramedullary nail fixation, while patients with a long life expectancy could be treated with more invasive surgery such as prosthetic reconstruction. The purpose of our study was to analyze the survival of patients treated surgically for long bone metastases, determining the prognostic factors affecting survival and analyzing the surgical complications and reoperation rates. Based on our results, we developed a prognostic score that helps to choose the best treatment for these patients. In addition, we compared the performance of our prognostic score with other previous prognostic models., Method: We investigated prospectively potential clinical and laboratory prognostic factors in 159 patients with metastatic bone disease who underwent surgery with intramedullary nail fixation or prosthetic reconstruction. Clinical data were collected, recording the following data: age and sex of patients, primary tumour and time of diagnosis, number (single or multiple) and presentation (synchronous or metachronous) of bone metastases, presence of visceral metastases. The following laboratory data were analyzed: hemoglobin, leukocyte counts, lymphocyte counts, platelets count, alkaline phosphatase, and C-reactive protein., Results: Our study showed that pathological C-reactive protein and primary tumour diagnosis were significant negative independent prognostic factors at 12-month survival. Based on our results, we created a score using C-reactive protein and primary tumour diagnosis, creating three different prognostic groups: (A) good prognosis primary tumour and physiological CRP with probability of survival at 12 months of 88.9 [80.1-98.5]; (B) bad prognosis primary tumour and physiological CRP or good prognosis primary tumour and pathological CRP with a probability of survival at 12 months of 56.7 [45.4-70.7]; (C) bad prognosis primary tumour and pathological CRP with a probability of survival at 12 months of 12.5 [5.0-28.3]. Using ROC multiple analysis, our score (AUC = 0.816) was the most accurate in predicting a 12-month survival compared to previous prognostic models., Discussion: Patients treated surgically for long bone metastases with a life expectancy over 12 months should be treated with more durable reconstruction, while patients with a life expectancy less than 12 months should be treated with less invasive surgery. The diagnosis of primary cancer and C-reactive protein are two very simple data which every orthopaedic surgeon in any community hospital can easily rely on for any decision-making in the surgical treatment of a complex patient as with a patient with skeletal metastases., Conclusion: Our prognostic score based on only two simple variables (C-reactive protein and primary tumour diagnosis) was able to predict the 12-month survival of patients treated surgically for long bone metastases and could be helpful in choosing the best treatment for these patients.

Purpose: Metal-on-metal (MOM) bearings may carry higher than expected revision rates and serious complications: an appropriate surveillance may be advocated. Aims of this paper were to (1) present the biennial experience of MOM surveillance in a tertiary centre, (2) describe the patients' adherence to monitoring, and (3) analyze the costs of the surveillance METHODS: The design of MOM surveillance was developed according to the guidelines of the Italian Society of Orthopaedics and Traumatology. The adherence to every follow-up was expressed as raw numbers and percentages. A cost analysis (direct and indirect costs) was conducted and projected in a five year time span., Results: About 61.1% of patients adhered to the first step of the surveillance, and 13.5% answered to a specific questionnaire about MOM implant. About 36.2% of the patients participated for the annual follow-up, and 18.1% entered the six month follow-up program. Of the implants, 2.5% required a revision. A two year surveillance costs €45,520.30, €236,443.98 (57.7%) including revisions. Five-year projected costs will be €23.113,64 (5.6%). Hospital indirect costs, including personnel working days, were €150,392.30 (36.7%). The estimated economic burden for seven years will be €409,949.92 (direct € 259,557.62, indirect €150,392.30)., Conclusion: Patients' adherence to MOM surveillance is modest and the rate of dropouts seems not to stop over the time. Most of the expenses are due to revision surgeries, as well as indirect costs. Economy of scale may be suggested to reduce the costs, involving as much MOM population as possible.

Purpose: Highly porous cups were developed to improve osseointegration and reduce the rate of aseptic loosening. Highly porous titanium cups could mix the reliability of titanium metal with an enhanced porosity, improving the bony ingrowth. The aim of this report was to assess the survival rates and reasons for revision of a highly porous titanium cup, Fixa Ti-Por (Adler Ortho, Milan, Italy), fabricated using an additive manufacturing., Methods: The Registry of Prosthetic Orthopedic Implants (RIPO), the Emilia-Romagna region arthroplasty registry, was enquired about cementless cups, implanted since July 2007. Ti-Por cups were compared to all the other cementless sockets, acting as a control group. The survival rates and reasons for revision were evaluated and compared. Comparisons with the same articular couplings were also provided., Results: When all the articular couplings were included, Ti-Por performed better, achieving a statistically higher survival rate than the control group (98.7% vs 97.9%) and a statistically lower incidence of cup aseptic loosening. In case of ceramic on polyethylene couplings, Ti-Por achieved similar survival rate: cup aseptic loosening in Ti-Por group was 0.2%, whereas the control group rated 0.4%. In ceramic-on-ceramic implants, the survival rate was similar in the two groups, Ti-Por achieving a cup aseptic loosening rate of 0.1% (vs 0.14% in the control group)., Conclusion: Highly porous titanium cups showed trustworthy results at eight years, reducing the rate of aseptic loosening. Longer follow-ups, ion analyses, and pre-clinical in vivo studies would be helpful to better define the reliability of these devices and their advantages.

Purpose: The effect of being obese on the long-term survival of total joint arthroplasty is persistently discussed. Considering only studies with large cohort of patients and meta-analysis, a high body mass index has been correlated with a higher incidence of complication but not univocally with a lower survival rate. In this study, we analyzed, retrospectively, the data of patients that received unicompartmental knee prostheses in order to examine if obesity has an effect on clinical outcomes., Methods: A retrospective multi-centre study was carried out on 4964 unicompartmental knee replacements between July 2000 and December 2016, the patients involved were 3976, with 988 bilateral cases. The patients were categorized into three groups: non-obese with a body mass index (BMI) < 30 kg/m 2 , obese with BMI ranged between 30 and 39 kg/m 2 , and morbidly obese (BMI ≥ 40 kg/m 2 ). The outcome was measured using the Cox proportional hazards model with end point UKA revision for any reasons. Results were stratified for sex, age, weight, and bi-laterality., Results: The morbidly obese group was significantly younger and required a significantly longer operating time. No statistical significant differences were observed considering the BMI groups in terms of type of insert, type of tibial component, prosthetic condyle, and prosthesis fixation (p > 0.05; chi-square test)., Conclusions: Obese and morbidly obese patients have as much to gain from total knee replacement as non-obese patients.

Purpose: Periprosthetic hip infection (PHI) is a devastating complication. The association between PHI and bearing surfaces as well as patient-related factors has been recently investigated, with contradictive outcomes. The dataset of Emilia-Romagna region Registry for Orthopaedic Prosthetic Implants (RIPO) has been assessed to investigate, if the bearing choice influenced the risk of septic loosening occurrence., Methods: RIPO data about 39,206 cementless total hip arthroplasties (THA), collected since 2003, were analysed. Age, gender, BMI, diabetes and bearing surfaces were evaluated. The end point of the study was the revision of at least a single component due to sepsis., Results: Adjusted and unadjusted survival rates showed that ceramic-on-ceramic (COC) implants had the lower incidence of PHIs, whereas metal-on-metal (MOM) THAs were significantly more prone to infection. In MOM cohort, stemmed implants were involved in 28 out of 30 cases. Among the demographical features and comorbid conditions, only diabetes statistically influenced the rate of sepsis., Conclusions: Bearing surfaces influenced the rate of PHI; in particular, stemmed MOM implants were at higher risk, probably due to metal debris consequent to taperosis. Despite the preliminary results, stemmed MOM THAs should be used with care, and diabetic patients should be warned about increased septic risks.

Purpose: Modular necks used in total hip replacement (THR) have become an increasingly discussed topic with the recent recall of multiple modular systems, but it is anticipated that outcomes for these devices are highly design-specific. The objectives of this study were to determine if the survivorship and complication rates of a specific modular femoral stem (PROFEMUR® Z, MicroPort Orthopedics Inc., Arlington, TN, USA) were significantly lower than those of all cementless fixed neck stems in an arthroplasty registry., Methods: The database of an arthroplasty registry was searched for all patients implanted with a specific modular stem and all those implanted with cementless fixed neck stems. Kaplan-Meier survivorship and complication rates were compared between the two groups., Results: The 12-year survivorship of the modular stem (95.8%) was not significantly less than that of all cementless fixed neck stems (96.1%). There was also no difference in revision rates for dislocation, periprosthetic fractures, aseptic loosening or septic loosening between the two groups., Conclusions: The use of the specific modular stem did not adversely affect long-term component survivorship or complication rates when compared to all cementless fixed neck THRs in an arthroplasty registry.

Purpose: Hip prostheses with metal-on-metal (MoM) coupling can release cobalt-chromium particles and ions. The aim of this work is to verify the correlation between particles in the synovial fluid and circulating ions., Methods: Forty patients were enrolled; particles from synovial fluid were analysed by SEM–EDX (Scanning Electron Microscopy-Energy Dispersion X-rays analysis) and levels of circulating Co and Cr were assayed by ICP-MS (inductively-coupled plasma mass spectrometry)., Results: In 16 cases we did not find any particles in the synovial fluid and the Co level in whole blood was 0.05–4.42 ppb; in seven with few particles the blood level was 2.2–15.6 ppb; in six cases with several particles the level was 5.0–54.3 ppb; finally, in 11 cases we isolated not only Co-Cr particles, but also Cr particles with low or absent Co and in these patients the circulating level of Co was 23.8–109.6 ppb. Co in serumand Cr level both whole blood and serum have shown a similar trend to Co; the correlation between all these values and the corresponding particles is statistically significant in all cases., Conclusion: Co and Cr both in serum and whole blood represents a systemic representation of the particle release at local level and can therefore be used to confirm a diagnosis and monitor the wear process of MoM articular prostheses.

The Register for Orthopaedic Prosthetic Implantation (RIPO) has been prospectively collecting data on hip prostheses performed in all the orthopaedic units in the region Emilia-Romagna since January 2000. The register aims to determine the characteristics of patients, evaluate the effectiveness of prostheses, and allow internal audit. Adherence to the register is compulsory (93% capture). By 31 December 2006 the register contained data on 35,041 primary total hip arthroplasty (THA), 14,613 hemiarthoplasties, and 5,878 revisions. All prosthetic components are registered on an individual basis. Survival analysis is done following the Kaplan Meier method. Cumulative survival rate at 7 years is 96.8% (95% CI: 96.4-97.1%) for THA and 97.6% (97.0-98.3%) for hemiarthroplasties. Multivariate analysis verified that survival of the THA is affected by pathology, where the worst conditions are rheumatoid arthritis, femoral neck fracture, and sequelae of coxitis or Paget's disease. Results are comparable to other major registers of Northern Europe and Australia.

Hylamer polyethylene was introduced in the 1990s as an alternative to conventional polyethylene. Its chemical and physical properties, and especially its high crystallinity, were claimed to improve resistance to wear. Initially Hylamer devices were sterilized by gamma radiation in air, then the technique was changed and gamma radiation was performed in the absence of oxygen. Clinical experience has shown the early loosening of some devices made from Hylamer. The aim of this study was to ascertain whether early wear and consequent osteolysis was linked to the sterilization method. We retrospectively compared 31 patients with hip prostheses with Hylamer liners sterilized by gamma radiation in air (group 1) with 30 patients with the same prosthesis, but sterilized in the absence of oxygen (group 2). The groups were similar for sex, age, disease, head diameter and material. Mean follow-up was 84 months and no clinical signs of failure were present. Radiographic measurement revealed that wear of group 1 was significantly greater than that of group 2 (0.23 mm/year vs 0.09 mm/year, p=0.001). Periacetabular and femoral osteolysis in group 1 was significantly greater than group 2. In conclusion, the method of sterilization might have influenced the outcome of Hylamer polyethylene liners.